Explosive composition



Patented Mar. 23, 1943 STAT 3231 s ear 8 2,314,807 EmLosIvE comosrrron Clarence H. Winning, Woodbury, N. 3., assignor to E. I. du Pont de Nemours & Company, Wilmington, Del, a corporation of Delaware No Drawing. Application November 26, 1940, Serial No. 367,217

11 Claims. (Cl. 52-11) erties, and is economically attractive. Ordinarily it is used with some particular sensitizing agent, either explosive or non-explosive in nature. While ammonium nitrate explosives have been used with greatsuccess, one disadvantage of this ingredient has always been evident, namely, that it has a great affinity for water. Because of this fact, there is a tendency for explosive compositions high in ammonium nitrate to become hard and set on storage in the presence of even small amounts of moisture. This brings about a decreased sensitiveness of the explosive and a lesser degree of uniformity in performance. The water resistance of ammonium nitrate explosives is generally low because of the presence of this very soluble salt.

An object of the present invention is an explosive composition containing at least one water-soluble salt and having improved water resistance. A further object is an ammonium nitrate explosive of enhanced water resistance. A still further object is an explosive containing ammonium nitrate wherein an ingredient is present which tends to prevent the harmful penetration of water. Additional objects will be disclosed as the invention is described more at length hereinafter.

I have found that the foregoing objects are accomplished by including rye flour as an in-' gradient in explosive compositions containing at least one water-soluble salt, said rye flour or meal being included inthe explosive composition .in pulverulent form and capable of functioning Nitrnglycerin percent 14.0 14. 0 Ammonium nitrate. (in 36. 5 36. 5 (alcium stem-ate 110.. 0.3 0.3 Sodium nitrate do" 34. i 34. 5 Wood pulp. do, 2. 7 2. 7 Wheat flour do 6. 0 Rye flour .do 6.0 Sulfur. .do 5.5 5. 5 (halk .do.. 0.5 0.5

r 100. 0 100. 0 l)ensityctgs./50lbs.-l%x8., ill ll0 Wale s! containing an explosive nitric ester, nitroglycerin, for example. It should be understood, however, that the invention is applicable as well to explosive compositions which contain no ingredient which is itself an explosive, for example, compositions containing non-explosive sensitizing agents. Many compositions, for instance, contain ammonium nitrate or other oxidizing agent sensitized with materials such as aluminum or other finely divided metals. Likewise, certain ammonium nitrate explosives a're sensitized with various forms of carbon, hydrocarbons and nitrated hydrocarbons, for example, parafiln, charcoal, dinitrotoluene, and the like. My invention is equally applicable to these compositions, since they contain the watersoluble salt which must be protected from wet conditions in the field. r

The advantages of my invention are'illustrated by the following specific embodiments, in which A and B represent ammonia dynamites of similar compositions, A containing wheat flour and B rye flour:

A very striking improvement in water resistance is shown in the ammonia dynamite above containing rye flour, in contrast to that containing wheat flour. The test consisted in immersing the partly opened dynamite cartridge in water in a metal tube for the time designated, detonation then being attempted by means of a blasting cap. In the case of the ammonia dynaas a protective agent against water for said salt.

My invention is applicable withadvantage to all explosive compositions containing a watersoluble salt, whether this salt is ammonium nitrate, sodium nitrate, a chlorate or perchlorate, or other soluble salt. I find it particularly important in the case of ammonium nitrate explosives, and especially in such compositions mite containing wheat flour, four failures to detonate resulted after '7 hours immersion of the explosive, whereas, withthe dynamite containing rye flour, four successful 'detonations i were obtained even after 48 hours.

The rye flour, when present in explosives of the type described, is capable of forming a cohesive and protective paste with the more or less dilute solutions produced when water comes in contact with the outer or exposed portion of explosives containing water-soluble salts. Ordinary flours, meals, and starches do not disperse satisfactorily and do not form protective pastes. of these latter materials, I may mention untreated wheat flour, corn meal, tapioca starch, and the like.

The dispersions formed by mixture of ordinary starch products with relatively small amounts of either water or dilut nitrate solutions, withoutapplication of heat. are such that there is a rapid separation of the flour, meal, starch, or the like. Rye flour acts differently in that the greater part of the material remains colloidally, dispersed and suspended on dilution of a relatively dry material with dilute nitrate solution even though no heat has been applied at any time.

When rye flour according to my invention is used in compositions such as ammonia dynamites, it appears thatthe entrance of the first traces of water brings about a paste or gel formation. This gelatinization in the outer portion of the explosive retards the rate of water penetration toward the interior of the explosive column. The gelatinous structure formed also prevents segregation of liquid or solid ingredients of the explosive such as would be caused by water penetration and softening of the composition. The cohesive gel or paste also decreases the loss of solid or liquid ingredients from partly opened cartridges by reason of gravity flow. The leaching of soluble salts is likewise lessened by the presence of the paste.

It will be understood that, in order to obtain the most favorable results, the rye meal or flour should be in finely divided condition. Preferably, said meal should be in a state of subdivision such that the major portion, that is more than 50%, will pass a (SO-mesh screen. Furthermore, the rye flour is included in the explosive composition in pulverulent form during the manufacture of the explosive composition, no paste being formed at that time: I do not intend to be limited to meal of. this degree of fineness, however. Likewise, I may wish to introduce into the explosive composition a small amount of a water-insoluble metal soap, such as calcium stearate, which will have a protective and coating effect on the ammonium nitrate against water or moisture. The presence of this latter ingredient, together with the rye flour. gives very beneficial results. The rye fiour is effective. however, without the presence of the water-insoluble soap. Preferably, said rye flour will be used in an amount not greater than and I find a quantity between 1% and 9% to be advantageous.

It will be understood-that I may use a meal made from the entire rye kernel or portions of said kernel which have a higher protein content, or other fractions of the rye.

The invention is applicable with great advantage in ammonia dynamites containing ammonium nitrate and nitroglycerin in amounts not exceeding 25%, for example, between 3% and 25%. It has important applications also in the case of compositions containing other high explosive compounds, such as nitrostarch. trinitrotoluene. and the like, in the presence of ammonium nitrate or other water-soluble salt. Furthermore. it is effective in the case of compositions in which the ammonium nitrate is sensitized by means of paraffin, dinitrotoluene, carbon, aluminum, other powdered metals and alloys, and many other materials.

As examples- The rye flour, according to my invention, has been stated to be present in pulverulent form during the manufacture of the explosives. It will be understood that this will exclude from the invention those explosives in which the ingredients are already protected by a water-insoluble envelope or coating. -Gelatinous explosives are excluded, for example, that is explosives wherein the nitroglycerin has been gelatinized by means of nitrocellulose. In such compositions, the rye flour would serve no useful purpose, since it is coated with the nitroglycerin-nitrocotton gel, hence could not combine with any entering water or water solution to form a protective rye paste on the surface of the water-soluble ingredients. Likewise, the rye flour would not be considered in pulverulent form, if embedded in, or coated or impregnated with a fused material insoluble in water or in aqueous solutions. A water-insoluble binder of the type described would interfere with the formation of a protective rye-water paste.

In general, my invention will not be considered to be as effective when nitroglycerin is present in amounts in excess of My invention has been described in detail in the foregoing. It will be apparent, however, that 7 many variations may be introduced in methods of application or in compositions without departure from the scope of the invention. I intend to limited therefore only by the following patent claims.

I claim:

1. An explosive composition containing not more than 25% liquid explosive, said composition comprising a water-soluble oxygen supplying in-' organic salt, a sensitizing agent, and rye flour in pulverulent form.

2. An explosive composition comprising ammonium nitrate, a sensitizing agent, and rye flour in pulverulent form.

3. An explosive composition containing not more than 25% liquid explosive, said composition comprising ammonium nitrate, an explosive sensitizing agent, and rye flour in pulverulent form.

4. The explosive composition of claim'3, wherein ,the sensitizing agent comprises nitroglycerin.

5. The explosive composition of claim 3, wherein the sensitizing agent comprises an aromatic nitrocompound.

6. An explosive composition comprising ammonium nitrate, a non-explosive sensitizing agent. and rye flour.

7. The explosive composition of claim 6. wherein the sensitizing agent comprises a powdered metal.

-8. An explosive composition comprising ammonium nitrate, between 3 and 25% nitroglycerin. and not more than 15% rye flour in pulverulent form.

9. The explosive composition of claim 8. in

, which the rye flour is present in a degree of fineness such that more than 50 ",2 thereof will pass a GO-mesh screen.

10. The explosive composition of claim 8, in

which the rye flour is present in an amount be-' 

